Lipopolysaccharide priming of alveolar macrophages for enhanced synthesis of prostanoids involves induction of a novel prostaglandin H synthase

• Published in: The Journal of biological chemistry Vol. 267; no. 21; pp. 14547 - 14550
• Main Authors: M G O'Sullivan, F H Chilton, E M Huggins, Jr, C E McCall
• Format: Journal Article
• Language: English
• Published: Bethesda, MD American Society for Biochemistry and Molecular Biology 25.07.1992
• Subjects: Animals; Bacteriology; Biological and medical sciences; Blotting, Northern; Blotting, Western; Cells, Cultured; DNA - genetics; DNA Probes; Enzyme Induction; Female; Fundamental and applied biological sciences. Psychology; Gas Chromatography-Mass Spectrometry; Lipopolysaccharides - metabolism; Macrophages, Alveolar - metabolism; Microbiology; Pathogenicity, virulence, toxins, bacteriocins, pyrogens, host-bacteria relations, miscellaneous strains; Precipitin Tests; Prostaglandin-Endoperoxide Synthases - biosynthesis; Prostaglandins - biosynthesis; Rabbits; Radioimmunoassay; RNA, Messenger - metabolism; Thromboxanes - metabolism; Northern blotting; Vertebrata; Mammalia; Enzyme; Lung; Prostanoid; Rabbit; Lipopolysaccharide; Biosynthesis; Lagomorpha; Macrophage; Prostaglandin synthase
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(18)42073-X

We report here that lipopolysaccharide (LPS) priming of rabbit alveolar macrophages leads to amplified synthesis of prostanoids, at least in part, by induction of a novel prostaglandin H synthase (PGH synthase). Rabbit alveolar macrophages were cultured with or without added LPS derived from Escherichia coli 0111:B4 for 4 h and then stimulated with opsonized zymosan (OPZ). LPS priming of alveolar macrophages resulted in enhanced release of thromboxane (TX) upon stimulation with OPZ, when compared to stimulated non-LPS controls. Addition of exogenous arachidonic acid to LPS-primed alveolar macrophages also resulted in increased production of TX. The LPS-induced increase in TX formation, in response to OPZ or arachidonic acid, was abolished by the addition of actinomycin D or cycloheximide during the priming period. Gas chromatography/mass spectrometry analysis indicated that levels of prostaglandins D2, E2, and F2 alpha, along with TX, were augmented in stimulated LPS-primed alveolar macrophages, implicating PGH synthase in the priming process. PGH synthase enzymatic activity, as determined by addition of arachidonic acid to macrophage sonicates, was markedly enhanced in LPS-primed alveolar macrophages. This correlated with increased PGH synthase levels detected by immunoprecipitation of 35S-labeled proteins and by Western blot analysis. Finally, Northern blot analysis using a cDNA probe to the recently described mitogen-inducible mouse PGH synthase revealed strong induction of approximately 4.3-kilobase mRNA in LPS-primed alveolar macrophages. Taken together, these results reveal that induction of a novel PGH synthase, probably the rabbit homologue of PGH synthase-2, plays a role in the enhanced synthesis of prostanoids by LPS-primed alveolar macrophages.